1. Field of the Invention
The present invention relates to electronic measuring devices and more particularly to gages for the measurement of machine shop workpieces.
2. Description of the Prior Art
Prior art electronic measuring devices for the measurement of internal and external workpiece dimensions are found in many different forms. One such device is described in U.S. Pat. No. 3,802,087 for "Measuring Apparatus" by Raiteri, issued Apr. 9, 1974. That patent discloses a gage for measuring the diameter of a workpiece between two relatively movable probes. One of the measuring probes is adapted for coarse travel and is connected to one of two relatively movable electrically coupled transducer elements. When the coarse-travel probe is positioned against one side of the workpiece, that probe is locked in position and a second, fine travel probe is connected to the other transducer element is moved into contact with the opposite side of the workpiece. The dimension of the workpiece between the probes can then be determined by processing electronic signals generated by the transducer element in a known manner, and no recalibration of the gage is required for the measurement of different dimensions or different workpieces. The transducer element of that gage continuously and accurately measures the separation of the two probes.
It is an object of the present invention to provide a measuring gage which has the advantages of the aforesaid gage, but which makes use of a single movable measurement probe having both coarse and fine travel components, thereby eliminating the need for individually adjusting two relatively movable probes against opposite sides of a workpiece and locking one of those probes in position before determining a measurement.